The present invention relates to a power assisted manually propelled vehicle, in particular a wheelchair, as well as to a power assisted wheel assembly thereof.
A German patent publication, DE 94 22 016 U1, discloses a power assisted caddie cart having two wheels. Each of the two wheels can have an integrated auxiliary drive for powering the cart. The auxiliary drive, which is a three-phase synchronous electric motor of the external rotor type, is operationally coupled to the respective wheel to deliver additional torque by means of a control system. One portion of the motor, the stator, is positioned on the rim of the driving wheel, which rim is rotatably mounted on the axle hub of a stationary wheel support.
The auxiliary drive comprises a rotatable wheel that encloses around the stationary wheel support. Rotor magnets are positioned on the inner side of the rotatable wheel. A tire and rim combination is screwed or bolted to a radially extending flange formed on the outer circumference of the rotatable wheel. The stationary wheel support is fixedly mounted to an axle having an elongate casing that houses batteries. The wheels are arranged on axle journals that are attachable by means of rotationally secure plug connections, which are combined with plug connections for control lines, power supply lines, and the like, leading into the wheels. Wire strain gauges are used as a torque sensor.
One object of the invention is to improve the vehicle of the type described above, in particular with regard to its structure and control system.
A further object resides in providing an improved power assisted wheelchair.